German patent DE-C2-41 04 871, ('871) relates to an applicator for a liquid application medium. A suitable liquid application medium, in the case of the known applicator, is a liquid which is intended for writing, drawing, painting or marking, but not a liquid adhesive. In the case of the known applicator, a relatively small opening in the base part is used for filling and, if appropriate, refilling, from the rear. After the filling or refilling operation, this relatively small opening is sealed by a releasable closure, which may be connected integrally to the base part, as a closure flap for example, via a film hinge. The shank-like receiving body for the liquid and the closure of the opening in the base part should be, in particular, of an oval or elongate cross-sectional shape. If the receiving container and its base part are not formed integrally but rather comprise two parts, in the case of which the base part, in particular, is pushed into the receiving container by means of a body forming a hollow profile, a permanent, non-releasable connection should be produced, for example, by welding, adhesive bonding or crimping. This type of connection requires a separate operation for the fastening step in each case.
There are certain adhesives, such as, in particular, so-called quick-action adhesives, which, in the raw state, are more fluid than water, that is to say have a lower viscosity than water. Cyanoacrylate belongs to this group of adhesives. This particular quick-action adhesive is inert with respect to the gases in the air, but polymerizes under the influence of water, including air moisture. In the event of filling an adhesive dispenser having the device features of the German patent '871, the highly fluid character of the relevant quick-action adhesive would not actually present any difficulties as far as filling the receiving container through the relatively small opening is concerned. However, difficulties may arise from the fact that the highly fluid filling jet carries along air moisture and, reacting with the air moisture, undergoes prepolymerization during the filling operation, it being possible for said prepolymerization to manifest itself by the formation of foam.
German patent DE-U1-84 07 703.8 has already disclosed an adhesive dispenser, in particular for cyanoacrylate, which has a receiving container, of which the cross section may be approximately oval and which is filled with the adhesive through its initially still free end-side opening. After the filling operation, the end-side opening of the receiving container is closed by a base part which projects into the receiving container by means of an open hollow cylinder and, in the base plane, has an annular flange which is designed with a larger diameter than the open hollow cylinder and comes to rest against the end surface of the receiving container. This means that, if a further-processing step were dispensed with, the base part can be drawn axially out of the receiving container again without any difficulty. Practical embodiments of this adhesive dispenser which are available on the market undergo, as a further processing step, ultrasonic welding for the purpose of connecting and sealing the receiving container and base part irreversibly with respect to one another. In order for this ultrasonic welding to be effective and for enclosed air to escape as the base part is pushed into the container, before it reaches the end stop, it is necessary here for a free air gap to remain between the inner wall surface of the receiving container and the hollow cylinder of the base part engaging in the receiving container. It has been shown that with this method of assembly, within the context of the tolerances, on the one hand, of the dimensions of the receiving container and base part and, on the other hand, of the filling, there is still residual air which remains in the filled and closed receiving container, or at least pressure being exerted on the filling composition by walls pressing thereon, and these situations result in an undesirable initial discharge of the adhesive when the adhesive dispenser is used for the first time. However, this is extremely undesirable precisely in the case of quick-action adhesives, which are intended to be applied as thinly and sparingly as possible in order for the definitive polymerization to be rapid and uniform. The known method of assembly also includes the risk, which may occur precisely in the case of welding defects, of it being possible, despite the ultrasonic welding, for a user, e.g. even a child, to lever off the base part from the receiving container using a relatively low amount of force, as a result of which the entire contents of the receiving container can then flow out suddenly. This then not only means that the adhesive dispenser is rendered completely useless and that its contents are destroyed, but also may be extremely harmful, or indeed hazardous, to objects and individuals.